A welding process is used to join one metal work surface to a second metal work surface by bringing abutting surfaces from the two work surfaces into a molten state. Welding can be performed in any of various ways. It can be performed with or without the application of pressure and can be performed with or without filler material. Heat to bring the surfaces of the work surfaces to a molten state can be provided by a gas flame, an electric arc, a chemical reaction, electrical resistance, or through friction between the two work surfaces as they are moved relative to one another.
Typically, a weld bead is formed at the abutting surfaces of the work surfaces during the welding process. When using an automated welding process it is important to monitor characteristics of the weld bead to ensure that the weld bead is within a predetermined range of parameters. If a certain characteristic is not within an acceptable parameter range, corrections need to be made to the welding process to ensure the quality of the weld bead.
A weld bead has a weld toe zone or region formed at the interface between the weld bead and each of the work surfaces. One important weld bead characteristic is the weld toe radius. As the radius of the weld toe increased, the fatigue performance of the final welded work surface increases. Thus, it is important to quantify the weld toe radius for determining the fatigue performance of the final welded work surface.
Various types of systems have been used to measure certain characteristics of the weld bead, such as U.S. Pat. No. 4,634,879 issued on Jan. 6, 1987 to Penney, U.S. Pat. No. 4,724,302 issued on Feb. 9, 1988 to Penney et al., and U.S. Pat. No. 5,264,678 issued on Nov. 23, 1993 to Powell et al., for example. These systems are often complex and expensive. Thus, it is desirable to monitor weld bead quality by focusing on the weld bead toe radius and to have a simplified process that can be used off-line or in real time that is less expensive than current processes.
The present invention is directed to overcoming one or more of the problems set forth above.